There were four errors in both the online and the print versions of this
paper. In the paragraph `Extracellular matrix synthesis is controlled by
HIF-1α under hypoxia' in Results on p. 1823, line 10, it should read
`Significantly less extractable proteoglycans were detected in
HIF-1α-null than in wild-type cultures after 44 hours exposure to 0.5%
oxygen (Fig. 5B)'.